Clamp attachment for lift trucks



Nov. 14, 1961 R. A. BRUDI ET AL 3,008,597

CLAMP ATTACHMENTYFOR LIFT TRUCKS Filed Nov. 12, 1957 5 Sheets-Sheet 1 INVENTORS RONALD A. BRUDI WYATT A. MILLIOUS yfwm ATTY.

Nov. 14, 1961 R. A. BRUDI ETAL CLAMP ATTACHMENT FOR LIFT TRUCKS s Sheets-Sheet 2 Filed Nov. 12, 1957 INVENTORS RONALD A. BRUDI BY WYATT A. MILLIOUS United States Patent This invention relates to an attachment for lift trucks, and more particularly to a stabilizing clamp attachment for use with such vehicles.

In certain materials handling operations in which lift trucks are utilized, it is frequently desirable that mechanism be provided on the truck which is capable of handling material such as heavy gauge tin and steel plate and the like, in such a manner that the material can be safely and readily engaged, transported and discharged by the lift truck and its mechanism. Often, it is desirable that the'lift truck mechanism or attachment be so constructed that the material carried thereby is dischargeable into a receiving rack or chute, for example, for a punch press or other shop machine. The shop machine may then be utilized to perform a particular operation on the plate as it is received in the rack or chute.

We have devised a very simple but effective attachment for lift trucks for handling such types of material in the above noted manner. In carrying out our invention we provide an inclined ramp assembly supported upon a carriage which is elevatable in the lifting mast of an industrial truck, and a stabilizing means operable with the inclined ramp to clamp therebetween and release therefrom such objects as tin or steel plate.

It is a principal object of this invention to provide a clamp attachment for use with lift trucks which is adapted to engage, transport, and discharge in a novel manner material handled thereby.

It is another object of this invention to provide a highly efficient and effective, but simple, mechanism for use in conjunction with lift trucks which is adapted to engage, carry and discharge certain types of material in a plane inclined to the longitudinal plane of the truck.

A further object of this invention is to provide in an attachment as aforesaid clamping, stabilizing and releasing means operable within a relatively small space.

Other objects and advantages of this invention will appear to persons skilled in the art in view of the following detailed description.

In the drawings:

FIGURE 1 is a view in perspective of the attachment of our invention shown in association with an industrial lift truck;

FIGURE 2 is a view in side elevation of the attachment showing stabilizing arm means therefor in two positions of operation; and

FIGURE 3 is a front view in elevation of the construction shown in FIGURE 2.

Referring now to the drawings in detail, an industrial lift truck of well known construction is shown generally at numeral and includes a body portion 12, drive axle and traction wheels 14 located adjacent the front of the truck, and control means 16 for operating the various hydraulic actuating means which are associated with the attachment and with a lifting mast construction shown generally at numeral 18. A steering wheel 20 may be seen through the mast 18 and is located in an operators station, the steering wheel being adapted to control rear steer wheels, not shown.

The lifting mast 18 is of well known construction generally comprises a pair of laterally spaced outer guide members 22, which may be supported upon the drive axle of the truck, and an inner slide construction 24 which is elevatable in telescoping relation to outer guide mem- ICC bers 22. An hydraulic hoist, chains and sprockets 26, 28, 30, respectively, are associated with the mast assembly 18 and areoperatively connected to a carriage 32 for actuating same vertically in a well known manner relative to the vertically movable inner slide assembly 24.

The carriage assembly 32 generally comprises a plurality of vertically spaced and transversely extending frame members 34 which are connected together at 'opposite ends thereof by a pair of laterally spaced and ver-' tically extending frame members 36, said latter members being also connected longitudinally thereof to a carriage portion 38 which may be attached to the inner slide assembly 24 by bracket and roller means, not shown, of

known construction, for guiding vertical movement of' the carriage 32 relative to the mast assembly.

Rigidly secured to the front surfaces of the lower pair of frame members 34 is a generally rectangular support- Secured adjacent the forward boundary" of each plate porand tion 46 and constructed to follow generally the contour thereof is a guideway 50 which is formed of a pair of laterally spaced and elongated bar members 51, the up per portions of which are formed to follow generally the configuration of the respective nose portion 48.

A stabilizing clamp arm is indicated generally at numeral 52 and comprises a pair of laterally spaced and generally triangular shaped support members 54 from the rear ends of which depend downwardly a pair of laterally spaced guide plates 56. A transversely extending frame member 58 fixes the lateral spacing of support plates 54 and functions as a stop member for a pivoted clamp pad 60. The clamp pad 60 is pivotably sup ported between the plates 56 by a transversely extending pivot shaft 62 which is mounted at opposite ends thereof in support plates 54, said clamping pad consisting of an elongated channel shaped member. The clamp ing pad is freely pivotable about shaft 62, being suspended therefrom such that the web of the channel is adapted to abut articles which may be supported upon ramps 44. Pivoting movement of the clamp pad in a clockwise direction, as seen in FIGURE 2, is limited by member 58. An adjustable stud or bolt 63 depends downwardly from and through an oversize opening in the member 58, and is secured to pad 60 to limit clockwise movement thereof. The bolt may be adjusted as desired to' vary the pivotal movement of clamp pad 60.

Pairs of generally vertically spaced rollers 64 are to tatably mounted outwardly of the opposite outer surfaces of the pair of depending support plate portions 56 on stub shafts for rolling engagement with guideways-'50, thus being adapted to guide the movements of the stabilizer arm assembly 52 according to the contour of cam tracks or guideways 50.

, Pivotably mounted upon a bracket and pin member 68, which is secured to and-projects centrally of support plate 40, is the cylinder end of an hydraulic cylinder and piston assembly 70, the rod end 72 of which is pivotably connected by bracket and pin means 74 to the center portion of transverse frame member 58. Flexible hoses,

76 and 78 conduct the flow of pressure fluid to one or the As best shown in FIGURE 2, wherein the stabilizing arm 52 is illustrated in extreme positions of elevation and incline, the rod 72 is extensible and retractible of the cylinder means to actuate the entire stabilizing clamp arm assembly 52 upwardly and downwardly relative to upper plate portions 46, the clamp arm assembly being guided by rollers 64 along the path of guide means 50.

In operation, the clamp arm assembly 52 is actuatable between the positions illustrated in FIGURE 2 to clamp one or a plurality of stacked sheets of metal plate or other material between the ramps 44 and the clamp pad 60, and to permit discharge of the material from the ramps 44 upon actuation of the clamp arm upwardly toward the horizontal position indicated. The clamp pad 60 pivots on shaft 62 to the extent necessary to insure substantially full engagement with the upper surface of a stack of material on ramps 44. The sheets of material, for example, to be engaged by the attachment arenormally stacked on edge in a rack in elevated position and at an angle perpendicular to the ramps 44. The rack is so constructed that the ramps 44 can be moved in under the bottom edges of such sheets at a given elevation on lifting mast 18, and the clamp arm 52 then actuated downwardly by cylinder and piston assembly 70 from its non-operative or horizontal position to a position of clamping engagement with the upper edges of such sheets of material. In view of the manner in which the sheets can be stacked, it will be seen that a very large number of them can be simultaneously engaged by the attachment, the number being limited by the length of the ramps and by the thickness of the sheets.

The sheets may be transported by the lift truck to a given location, such as adjacent a shop machine, and deposited in a feeder rack for the machine, for example. Such a feeder rack would normally include load supporting members inclined at the same angle as the ramps 44, whereby the attachment would be lowered in lifting mast 18 until portions of the bottom edges of the sheets rested upon the support members, following which the clamp arm 52 would be raised to horizontal position and the truck backed away from the rack. Such a rack, of course, forms no part of the present invention.

The height of the attachment, of course, can be varied in manufacture as desired to provide greater or lesser length of guideways 50 for the handling of relatively wider or narrower sheets of material, as the case may be. It will also be apparent to persons skilled in the art that upper plate portions 46 need not be made integral with the lower triangular ramp portions of plates 42. The upper plate portions 46 couldbe secured as by bolts, for example, to the sides of the triangular plate portions. Adjustment openings in the triangular plate portions could be provided whereby portions 46 could be adjusted vertically relative to the triangular plate portions, thereby permitting a wider range of size of sheet material to be handled by the attachment. Numerous variations in construction permitting such adjustability will readily appear to persons versed in the art.

The use of curved guideways 50 in the manner described has the very desirable result of minimizing the 1 height, weight, and general bulk of our attachment. Raising the clamp arm 52 to a substantially horizontal position by means of the guideways permits the entire clamp arm to clear a stack of inclined sheets as the truck is backed away from the'load after discharge thereof, I as above described. If the upper portions of the guideways were not curved rearwardly, it would be necessary to extend the. forwardly inclined portions thereof a distance sufiicient to insure that the forward end of the clamp pad would, when raised in inclined position, clear the rearwardmost sheet of an inclined stack of material as the truck was moved forwardly to engage, or rearwardly to disengage a load. Obviously, such an arrangement would add substantially to the height, weight, and general bulk of the attachment. In other words, the latter mentioned construction would be far less compact than .the preferred construction since substantially greater'elevation of the clamp arm 52 as a whole would be re quired during loading and unloading operations wherein the clamp arm would remain parallel to the ramps 44.

Sheets of stacked material, as aforesaid, can also be engaged, transported and disengaged by my device while lying in a plane substantially parallel to the plane of the ramps 44.

While only one embodiment of this invention has been described in detail with respect to the accompanying drawing, it will be apparent to persons skilled in the art that many changes and modifications in the construction, form and arrangement of parts may readily be made without departing from the scope of the invention.

We claim:

1. An attachment for lift trucks having a lifting mast construction located adjacent one end thereof comprising support. means operatively connected to the mast construction for vertical movement relative thereto, downwardly inclined ramp means secured to the support means, extending forwardly thereof and adapted to engage a load for transporting same, guide means extending upwardly of the inclined ramp means on a line perpendicular to the incline of said ramp, a forwardly extending clamp arm means operatively connected to the guide means for upward and downward inclined movement on a line substantially perpendicular to and in a plane generally parallel to the plane of the inclined ramp means, and motor means for actuating said clamp arm means relative to said guide means as aforesaid, said inclined ramp means and clamp arm being together adapted to engage and clamp materials for transport by said truck in an inclined position relative thereto, and said guide means being turned generally rearwardly in the upper portion thereof in order to effect additional arcuate opening movement of the clamp arm when the motor means actuates the clamp arm to the upper portion of the guide means.

2. An attachment as claimed in claim 1 wherein said clamp arm means includes an articulated pad portion pivotable to substantially fully engage the upper surface of a stack of articles clamped between said clamp arm means and said ramp means.

3. An attachment as claimed in claim 1 wherein that portion of the guide means which extends below the upper rearwardly turned portion thereof is essentially transverse to the inclined ramp means.

4. In an attachment for use with lift trucks, a downwardly inclined load engaging means extending forwardly of and supported by the lift truck adjacent one end thereof, a clamp arm supported by the lift truck above the load engaging means, a guideway extending substantially perpendicular to the load engaging means throughout a lower portion thereof and being turned generally rearwardly in an upper portion thereof, said clamp arm being operatively connected to said guideway for guided movement relative to said load engaging means, and motor means for actuating the clamp arm along said guideway, whereby said clamp arm is movable from the lower portion of the guideway, wherein the clamp arm extends above and in substantially parallel relation to the load engaging means, to the upper portion of the guideway, wherein the clamp arm extends above and in non parallel relation to the load engaging means.

5. An attachment for lift trucks comprising attachment support means connected to the truck adjacent one end thereof, generally triangular shaped ramp means connected to the support means to extend forwardly thereof and having a forwardly and downwardly extending load engagingsurface associated therewith, a curved guide means extending generally upwardly perpendicular to and then rearwardly relative to said load engaging surface, a clamp arm extending forwardly of the support means and connected to the guide means for initial parallel guided movement relative to the load engaging surface and for subsequent opening arcuate movement relative to said surface, and motor means for actuating said clamp arm in said guide means to effect said movements thereof.

6. An attachment as claimed in claim 5 wherein said motor means comprises a hydraulic cylinder and piston assembly pivotably connected at opposite ends thereof to the support means and to the clamp arm for effecting actuation of the clamp arm in said guide means, said clamp arm including an articulated pad portion conformable to the surface of a load carried by said load engaging surface but which is non-parallel to said load engaging surface.

7. An attachment for lift trucks, comprising a forwardly and downwardly inclined load engaging means, load clamping means movable to and from said load engaging means, including two parallel tracks extending upwardly from and substantially perpendicular to said load engaging means throughout most of their length and having upwardly and rearwardly extending upper end portions, frame means supported by said tracks, two spaced rollers on opposite sides of said frame means engaging said tracks, and a forwardly extending member mounted on said frame means, said member extending parallel to said load engaging means when both rollers on each side are #011 the perpendicular portion of said tracks and generally horizontal when one roller on each side is on the perpendicular portion and the other roller on each side is on the upper end portion of said tracks.

8. An attachment for lift trucks, comprising a forwardly and downwardly inclined load engaging means, load clamping means movable to and from said load engaging means, including a track extending upwardly fnom and substantially perpendicular to said load engaging means throughout most of its length and having an upwardly and rearwardly extending upper end portion, frame means supported by said track, two spaced rollers on said frame means engaging said track, and a forwardly extending member mounted on said frame means and extending therefrom parallel to said lead engaging means when both rollers are on the perpendicular portion of the track and extending outward and away from said load engaging means when one roller is on the perpendicular portion and the other roller is on the upper end portion of said track.

References Cited in the file of this patent UNITED STATES PATENTS 1,763,351 Gfrorer June 10, 1930 2,724,520 Overbeck Nov. 22, 1955 2,874,862 Farmer et a1 Feb. 24, 1959 

